"He has done fantastic for us and it's not a bad thing, all the uncertainty is now done and we can move on.

"The ball was always in Demba's court. But this club is bigger than any player for sure."

Chelsea officials held initial discussions with Ba's representatives earlier this week but had been unable to reach an agreement.

The Senegal frontman, who joined Newcastle on a free transfer from West Ham in June 2011, already has 13 goals to his name this season and has been pursued by several clubs.

Newcastle released a statement which read: "Newcastle United can confirm Chelsea Football Club has made an official offer for Demba Ba which has triggered the release clause in the player's contract.

"The club has given the player permission to speak to Chelsea FC and therefore he will not be included in the squad for tonight's game with Everton."

Chelsea's interim manager Rafael Benitez is keen to add another striker to his squad to provide competition for Fernando Torres, claiming the club's £50m record signing would have no problem with being used in a rotation system.

Benitez has also been linked with moves for Atletico Madrid striker Radamel Falcao and Bayer Leverkusen's Andre Schurrle.